The Hybridoma Core Facility will be used by at least 23 UM-MAC investigators who are pursuing a variety of research projects that require monoclonal antibodies. The Hybridoma Facility (HF) is a research laboratory, the purpose of which is to generate somatic-cell hybrids (hybridomas) that produce monoclonal antibodies of desired specificity. It is currently supported by the Michigan Diabetes Research and Training Center (MDRTC), and by the University of Michigan Multipurpose Arthritis Center (UM-MAC), for use by investigators within these centers. It is also used by a wide range of investigators at the University of Michigan on a recharge basis. Services provided include immunization of mice, fusion of B lymphocytes with myeloma cells to create hybridomas, subcloning and cryopreservation of hybridomas, and production of ascites in mice. Consultation is available from the Hybridoma Core director in design of screening assays to insure efficient detection of the desired monoclonal antibodies. The majority of hybridomas produced in the core are of murine origin, but rat and human hybridomas have also been produced. Since its establishment in 1980 the Hybridoma Facility has produced monoclonal antibodies against a wide variety of lymphocyte surface antigens, tumor cell antigens, purified proteins, hormones, hormone receptors and recombinant proteins. In the first 3 1/2 years of UM-MAC support more than 50 fusions were performed for UM-MAC investigators. Subcloning was performed for >250 hybridomas, and 77 monoclonal antibodies were produced in murine ascites. The current proposal will allow this facility to take advantage of ongoing technical advances in monoclonal antibody production that use both somatic cell fusion and recombinant library approaches. An expert advisory committee will assist the director and associate director in the evaluation of new technologies for production of monoclonal antibodies from rodent, human and avian sources, as well as novel isotype switching strategies. Demonstration projects using new technologies will be undertaken in collaboration with laboratories of UM-MAC investigators. Through these initiatives, the Hybridoma Core will remain on the cutting edge of monoclonal antibody technology, and continue to provide optimal service to UM-MAC investigators.